The integration of metamaterials into building elements

Abstract

The building industry continues to rely on homogeneous materials for acoustic insulation despite the progress of research into acoustic metamaterials. With the inevitable densification of housing, the severity of noise pollution within residential living environments is escalating. While the insulation of high-frequency audible sound through building elements is often relatively good between 1 and 5 kHz, the overall acoustic transmission loss performance is often significantly limited by two specific frequency regions. The mass air mass resonance band, and the coincidence band. We present the results of an investigation into the use of metastructures and metasurfaces to improve transmission loss in these frequency regions with a focus on scalable implementation. These metastructures are metamaterial systems constructed from impedance change elements, surface variations and vibroacoustic resonant elements. The performance of selected systems from this research are presented. Experimental and modeling results are in good qualitative agreement and promising diffuse-field testing results indicate significant attenuation within the targeted band regions. The merits of each technique are analysed, and results indicate which methods are most effective at either mitigating or shifting the regions of poor transmission loss outside of the most important part of the audible frequency region.